1. Field of the Invention
The present invention relates to tolerance rings and more particularly to improvements in tolerance rings to provide for mounting in thin panels; centered and half centered mounting configurations; and restoring the usefullness of worn shafts.
2. Description of the Prior Art
Tolerance rings are generally formed as split ring members having a corrugated surface and are sandwiched between two cylindrical surfaces, that is, an outer cylindrical surface and an inner cylindrical surface, to provide frictional engagement between two members having the respective cylindrical surfaces. The corrugations on the ring may protrude inwardly from an outer surface thereof, outwardly from an inner surface thereof or alternatively inwardly and outwardly. Such tolerance rings are illustrated in U.S. Pat. Nos. 3,142,887 and 3,145,547. The corrugations on the tolerance rings may be of varying heights or may be arranged in more than one row around the circumference of the ring as illustrated in U.S. Pat. Nos. 3,700,271; 3,838,928 and 4,286,894.
In some applications it is desirable to mount a cylindrical member within a hole in a thin sheet panel and to keep the cylindrical member in a fixed axial position within the hole. Tolerance rings may be used to provide an increased frictional engagement between the cylindrical member and the hole in the panel, however, if there is a significant amount of vibration present, the tolerance ring may tend to move axially even to a point of disengagement with the hole, thereby resulting in a loss of frictional engagement between the cylindrical member and the panel. Thus, it would be desirable to have a means for preventing such axial movement of the tolerance ring.
In other applications, the tolerance ring is used in what is referred to as a centered arrangement or half centered arrangement especially when a tight concentricity specification is used or where greater radial shock loads are anticipated. In such a mounting arrangement, shoulders are provided adjacent to one or both axial ends of the tolerance ring on either the inner member or outer member. The shoulders have a height such that they do not generally engage the surface of the other member unless there is some radial load that moves the two members out of concentricity. The height of the shoulders is designed such that the shoulders will engage the opposing member just prior to the point at which the corrugations in the tolerance ring would reach their elastic limit during a crushing of the corrugations due to the radial load. Thus, the corrugations would retain their resiliency and usefullness despite occasional radial loads which would otherwise impair their usefullness. However, in such an arrangement at least one of the two members must be specially machined to provide the shoulders which adds to the costs of the parts. Further, in some applications, it may not be possible to machine the shoulders into the parts, especially if problems develop after the parts have been fabricated. Therefore, it would be an improvement if a means were provided for allowing a centered or half centered arrangement without the use of shoulders being formed on one or both adjacent members.
In still other applications, particularly those applications where a bearing is mounted on a shaft, the shaft often times becomes worn in the area of engagement with the bearing inner race, thus causing slippage between two parts due to a deterioration of the frictional engagement between the shaft and the surrounding bearing. In the past this has been rectified by a multi-step procedure including a cleaning of the shaft, welding additional material onto the shaft in the worn area, grinding the welded material down to provide a smooth cylindrical surface in the previously worn area, heat treating the area to provide the required hardness and finishing the treated area to provide a smooth engaging surface. These steps are labor intensive and quite costly and therefore it would be an improvement if there were provided a more economical yet satisfactory means for upgrading the frictional engagement between a worn inner cylindrical member and an outer member with a cylindrical opening.